Actually, the use of DOS-style maps are one of the things I like about the new BG3. Not only because one big map reduces the loading times, but also because now we have 3d maps, so you can now use heights, jumps and fly as in PNP.
I didn-t read anywhere that we will have one map per act,that we do not have a big area map or that we cannot go back to previous areas, so I will reserve my opinion on the matter.
I'm agree but a total DOS map style will be not my cup of tea and too far from BG style. I think a good deal will be large map with unique identity "a village with forest around and rural field but not a winter forest near a poisoned swamp near a city near a lava lake...". (I don't want elemental terrain mechanic everywhere like TNT barrel in every house...)
The presence of a map world and the freedom of explore and back to previous areas are essential.